1. Field of the Invention
The present invention relates to a multi-beam laser apparatus, and more particularly, to a multi-beam laser apparatus capable of easily producing a plurality of beamlets, and enhancing quality and uniformity in machining by adjusting paths of the beamlets obtained.
2. Description of the Related Art
Recently, in a thin film transistor for use in a liquid display, a poly silicon film with high carrier mobility is utilized for a channel layer. Generally, the poly silicon film of the thin film transistor is manufactured by forming an amorphous silicon film on a glass substrate and irradiating a laser beam onto the amorphous silicon film.
Here, to ensure higher efficiency of the process, the thin film transistor requires a beam splitter splitting a laser beam into a plurality of beamlets.
FIG. 1 shows a conventional beam splitter.
Referring to FIG. 1, in the beam splitter, a laser beam 11 generated from a light source passes through first and second beam splitting units 12a and 12b and is split into three beamlets. The beamlet passed through the second beam splitting unit 12b is reflected by a reflective mirror 13.
Accordingly, the laser beam 11 can be split into the three beamlets to be irradiated onto a workpiece such as a glass substrate. At this time, a collimator 14 such as a lens for focusing the three beamlets is disposed between the beam splitting units 12a and 12b and the workpiece 15.
The conventional beam splitter splits the one beam into the three beams to increase efficiency associated with e.g., laser annealing, however requiring the beam splitting units as many as the beamlets to be split. That is, as shown in FIG. 1, to split the one beam into the three beams, three optical units, i.e., two beam splitting units and one reflective mirror are necessary.
As a result, a greater number of the required beamlets complicate a structure of the optical system and pose a difficulty to precise control.